* routing bug?
@ 2011-11-18 12:00 Pozsár Balázs
2011-11-18 12:48 ` Sven-Haegar Koch
0 siblings, 1 reply; 7+ messages in thread
From: Pozsár Balázs @ 2011-11-18 12:00 UTC (permalink / raw)
To: linux-kernel; +Cc: Tamási János
Hi all,
I have been struggling with this not easily reproducible issue since a
while. I am using linux kernel v3.1.0, and sometimes routing to a few IP
addresses does not work. What seems to happen is that instead of sending
the packet to the gateway, the kernel treats the destination address as
local, and tries to gets its MAC address via ARP.
For example, now my current IP address is 172.16.1.104/24, the gateway
is 172.16.1.254:
|# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC
inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:230772 errors:0 dropped:0 overruns:0 frame:0
TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb)
Interrupt:17
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0
172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0
|
I can ping a few addresses, but not 172.16.0.59:
|# ping -c1 172.16.1.254
PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data.
64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms
--- 172.16.1.254 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms
root@pozsybook:~# ping -c1 172.16.0.1
PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data.
64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms
--- 172.16.0.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms
root@pozsybook:~# ping -c1 172.16.0.2
PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data.
64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms
--- 172.16.0.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms
root@pozsybook:~# ping -c1 172.16.0.59
PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data.
From 172.16.1.104 icmp_seq=1 Destination Host Unreachable
--- 172.16.0.59 ping statistics ---
1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
|
When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req
was sent:
|# tcpdump -n -i eth0|grep ARP
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28
|
and /proc/net/arp has an incomplete entry for 172.16.0.59:
|# grep 172.16.0.59 /proc/net/arp
172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0
|
Please note, that 172.16.0.59 /is/ accessible from this LAN from other
computers.
Does anyone have any idea of what's going on? Thanks,
Balazs Pozsar
ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: routing bug? 2011-11-18 12:00 routing bug? Pozsár Balázs @ 2011-11-18 12:48 ` Sven-Haegar Koch 2011-11-18 13:09 ` Eric Dumazet 0 siblings, 1 reply; 7+ messages in thread From: Sven-Haegar Koch @ 2011-11-18 12:48 UTC (permalink / raw) To: Pozsár Balázs Cc: Linux-Kernel-Mailinglist, Tamási János, netdev [-- Attachment #1: Type: TEXT/PLAIN, Size: 3834 bytes --] Added netdev list to CC:, there you should have a higher chance of a usefull answer. On Fri, 18 Nov 2011, Pozsár Balázs wrote: > Hi all, > > I have been struggling with this not easily reproducible issue since a while. > I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses > does not work. What seems to happen is that instead of sending the packet to > the gateway, the kernel treats the destination address as local, and tries to > gets its MAC address via ARP. > > For example, now my current IP address is 172.16.1.104/24, the gateway is > 172.16.1.254: > > |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC > inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 > TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) > Interrupt:17 > > # route -n > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use Iface > 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 > 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 > | > > I can ping a few addresses, but not 172.16.0.59: > > |# ping -c1 172.16.1.254 > PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. > 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms > > --- 172.16.1.254 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.1 > PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. > 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms > > --- 172.16.0.1 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.2 > PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. > 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms > > --- 172.16.0.2 ping statistics --- > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms > root@pozsybook:~# ping -c1 172.16.0.59 > PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. > From 172.16.1.104 icmp_seq=1 Destination Host Unreachable > > --- 172.16.0.59 ping statistics --- > 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms > | > > When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was > sent: > > |# tcpdump -n -i eth0|grep ARP > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode > listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes > 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 > | > > and /proc/net/arp has an incomplete entry for 172.16.0.59: > > |# grep 172.16.0.59 /proc/net/arp > > 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 > | > > Please note, that 172.16.0.59 /is/ accessible from this LAN from other > computers. > > > Does anyone have any idea of what's going on? Thanks, > > > Balazs Pozsar > > ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > -- Three may keep a secret, if two of them are dead. - Ben F. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: routing bug? 2011-11-18 12:48 ` Sven-Haegar Koch @ 2011-11-18 13:09 ` Eric Dumazet 2011-11-18 13:23 ` Pozsár Balázs 0 siblings, 1 reply; 7+ messages in thread From: Eric Dumazet @ 2011-11-18 13:09 UTC (permalink / raw) To: Sven-Haegar Koch Cc: Pozsár Balázs, Linux-Kernel-Mailinglist, Tamási János, netdev Le vendredi 18 novembre 2011 à 13:48 +0100, Sven-Haegar Koch a écrit : > Added netdev list to CC:, there you should have a higher chance of a > usefull answer. > > On Fri, 18 Nov 2011, Pozsár Balázs wrote: > > > Hi all, > > > > I have been struggling with this not easily reproducible issue since a while. > > I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses > > does not work. What seems to happen is that instead of sending the packet to > > the gateway, the kernel treats the destination address as local, and tries to > > gets its MAC address via ARP. > > > > For example, now my current IP address is 172.16.1.104/24, the gateway is > > 172.16.1.254: > > > > |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC > > inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 > > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > > RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 > > TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 > > collisions:0 txqueuelen:1000 > > RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) > > Interrupt:17 > > > > # route -n > > Kernel IP routing table > > Destination Gateway Genmask Flags Metric Ref Use Iface > > 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 > > 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 > > | > > > > I can ping a few addresses, but not 172.16.0.59: > > > > |# ping -c1 172.16.1.254 > > PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. > > 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms > > > > --- 172.16.1.254 ping statistics --- > > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > > rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms > > root@pozsybook:~# ping -c1 172.16.0.1 > > PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. > > 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms > > > > --- 172.16.0.1 ping statistics --- > > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > > rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms > > root@pozsybook:~# ping -c1 172.16.0.2 > > PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. > > 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms > > > > --- 172.16.0.2 ping statistics --- > > 1 packets transmitted, 1 received, 0% packet loss, time 0ms > > rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms > > root@pozsybook:~# ping -c1 172.16.0.59 > > PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. > > From 172.16.1.104 icmp_seq=1 Destination Host Unreachable > > > > --- 172.16.0.59 ping statistics --- > > 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms > > | > > > > When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was > > sent: > > > > |# tcpdump -n -i eth0|grep ARP > > tcpdump: verbose output suppressed, use -v or -vv for full protocol decode > > listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes > > 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 > > | > > > > and /proc/net/arp has an incomplete entry for 172.16.0.59: > > > > |# grep 172.16.0.59 /proc/net/arp > > > > 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 > > | > > > > Please note, that 172.16.0.59 /is/ accessible from this LAN from other > > computers. > > > > > > Does anyone have any idea of what's going on? Thanks, > > > > > > Balazs Pozsar > > > > ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 > > > > -- Could you send us result of : ip route get 172.16.0.59 ip route list cache match 172.16.0.59 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: routing bug? 2011-11-18 13:09 ` Eric Dumazet @ 2011-11-18 13:23 ` Pozsár Balázs 2011-11-18 13:33 ` Eric Dumazet 0 siblings, 1 reply; 7+ messages in thread From: Pozsár Balázs @ 2011-11-18 13:23 UTC (permalink / raw) To: Eric Dumazet Cc: Sven-Haegar Koch, Linux-Kernel-Mailinglist, Tamási János, netdev On 2011-11-18 14:09, Eric Dumazet wrote: > Le vendredi 18 novembre 2011 à 13:48 +0100, Sven-Haegar Koch a écrit : > >> Added netdev list to CC:, there you should have a higher chance of a >> usefull answer. >> >> On Fri, 18 Nov 2011, Pozsár Balázs wrote: >> >> >>> Hi all, >>> >>> I have been struggling with this not easily reproducible issue since a while. >>> I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses >>> does not work. What seems to happen is that instead of sending the packet to >>> the gateway, the kernel treats the destination address as local, and tries to >>> gets its MAC address via ARP. >>> >>> For example, now my current IP address is 172.16.1.104/24, the gateway is >>> 172.16.1.254: >>> >>> |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC >>> inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 >>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 >>> RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 >>> TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 >>> collisions:0 txqueuelen:1000 >>> RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) >>> Interrupt:17 >>> >>> # route -n >>> Kernel IP routing table >>> Destination Gateway Genmask Flags Metric Ref Use Iface >>> 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 >>> 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 >>> | >>> >>> I can ping a few addresses, but not 172.16.0.59: >>> >>> |# ping -c1 172.16.1.254 >>> PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. >>> 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms >>> >>> --- 172.16.1.254 ping statistics --- >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>> rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms >>> root@pozsybook:~# ping -c1 172.16.0.1 >>> PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. >>> 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms >>> >>> --- 172.16.0.1 ping statistics --- >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>> rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms >>> root@pozsybook:~# ping -c1 172.16.0.2 >>> PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. >>> 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms >>> >>> --- 172.16.0.2 ping statistics --- >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>> rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms >>> root@pozsybook:~# ping -c1 172.16.0.59 >>> PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. >>> From 172.16.1.104 icmp_seq=1 Destination Host Unreachable >>> >>> --- 172.16.0.59 ping statistics --- >>> 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms >>> | >>> >>> When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was >>> sent: >>> >>> |# tcpdump -n -i eth0|grep ARP >>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode >>> listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes >>> 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 >>> | >>> >>> and /proc/net/arp has an incomplete entry for 172.16.0.59: >>> >>> |# grep 172.16.0.59 /proc/net/arp >>> >>> 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 >>> | >>> >>> Please note, that 172.16.0.59 /is/ accessible from this LAN from other >>> computers. >>> >>> >>> Does anyone have any idea of what's going on? Thanks, >>> >>> >>> Balazs Pozsar >>> >>> ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 >>> >>> -- >>> > Could you send us result of : > > ip route get 172.16.0.59 > ip route list cache match 172.16.0.59 > I did not tell you in my first mail, that some times different hosts are reachable and unreachable. I will try to not confuse you :) As of now, 172.16.0.59 is OK, and 172.16.0.37 is NOT OK. Also, 172.16.0.64 is OK now, and 172.16.0.42 is NOT OK now. The two commands you have requested give the following output for these IP addresses: These are OK: # ip route get 172.16.0.64 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 cache # ip route get 172.16.0.59 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 cache These are NOT OK: # ip route get 172.16.0.37 172.16.0.37 dev eth0 src 172.16.1.22 cache <redirected> ipid 0x97a4 # ip route get 172.16.0.42 172.16.0.42 dev eth0 src 172.16.1.22 cache <redirected> ipid 0x0d21 These are OK: # ip route list cache match 172.16.0.59 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 cache # ip route list cache match 172.16.0.64 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 cache These are NOT OK: # ip route list cache match 172.16.0.37 172.16.0.37 dev eth0 src 172.16.1.22 cache <redirected> ipid 0x97a4 172.16.0.37 from 172.16.1.22 dev eth0 cache <redirected> ipid 0x97a4 172.16.0.37 from 172.16.1.22 dev eth0 cache <redirected> ipid 0x97a4 # ip route list cache match 172.16.0.42 172.16.0.42 dev eth0 src 172.16.1.22 cache <redirected> ipid 0x0d21 172.16.0.42 from 172.16.1.22 dev eth0 cache <redirected> ipid 0x0d21 How can I fix this? Thanks! ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: routing bug? 2011-11-18 13:23 ` Pozsár Balázs @ 2011-11-18 13:33 ` Eric Dumazet 2011-11-18 13:38 ` Pozsár Balázs 0 siblings, 1 reply; 7+ messages in thread From: Eric Dumazet @ 2011-11-18 13:33 UTC (permalink / raw) To: Pozsár Balázs Cc: Sven-Haegar Koch, Linux-Kernel-Mailinglist, Tamási János, netdev Le vendredi 18 novembre 2011 à 14:23 +0100, Pozsár Balázs a écrit : > On 2011-11-18 14:09, Eric Dumazet wrote: > > Le vendredi 18 novembre 2011 à 13:48 +0100, Sven-Haegar Koch a écrit : > > > >> Added netdev list to CC:, there you should have a higher chance of a > >> usefull answer. > >> > >> On Fri, 18 Nov 2011, Pozsár Balázs wrote: > >> > >> > >>> Hi all, > >>> > >>> I have been struggling with this not easily reproducible issue since a while. > >>> I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses > >>> does not work. What seems to happen is that instead of sending the packet to > >>> the gateway, the kernel treats the destination address as local, and tries to > >>> gets its MAC address via ARP. > >>> > >>> For example, now my current IP address is 172.16.1.104/24, the gateway is > >>> 172.16.1.254: > >>> > >>> |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC > >>> inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 > >>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > >>> RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 > >>> TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 > >>> collisions:0 txqueuelen:1000 > >>> RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) > >>> Interrupt:17 > >>> > >>> # route -n > >>> Kernel IP routing table > >>> Destination Gateway Genmask Flags Metric Ref Use Iface > >>> 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 > >>> 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 > >>> | > >>> > >>> I can ping a few addresses, but not 172.16.0.59: > >>> > >>> |# ping -c1 172.16.1.254 > >>> PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. > >>> 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms > >>> > >>> --- 172.16.1.254 ping statistics --- > >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms > >>> rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms > >>> root@pozsybook:~# ping -c1 172.16.0.1 > >>> PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. > >>> 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms > >>> > >>> --- 172.16.0.1 ping statistics --- > >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms > >>> rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms > >>> root@pozsybook:~# ping -c1 172.16.0.2 > >>> PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. > >>> 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms > >>> > >>> --- 172.16.0.2 ping statistics --- > >>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms > >>> rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms > >>> root@pozsybook:~# ping -c1 172.16.0.59 > >>> PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. > >>> From 172.16.1.104 icmp_seq=1 Destination Host Unreachable > >>> > >>> --- 172.16.0.59 ping statistics --- > >>> 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms > >>> | > >>> > >>> When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was > >>> sent: > >>> > >>> |# tcpdump -n -i eth0|grep ARP > >>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode > >>> listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes > >>> 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 > >>> | > >>> > >>> and /proc/net/arp has an incomplete entry for 172.16.0.59: > >>> > >>> |# grep 172.16.0.59 /proc/net/arp > >>> > >>> 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 > >>> | > >>> > >>> Please note, that 172.16.0.59 /is/ accessible from this LAN from other > >>> computers. > >>> > >>> > >>> Does anyone have any idea of what's going on? Thanks, > >>> > >>> > >>> Balazs Pozsar > >>> > >>> ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 > >>> > >>> -- > >>> > > Could you send us result of : > > > > ip route get 172.16.0.59 > > ip route list cache match 172.16.0.59 > > > > I did not tell you in my first mail, that some times different hosts are > reachable and unreachable. I will try to not confuse you :) > As of now, 172.16.0.59 is OK, and 172.16.0.37 is NOT OK. > Also, 172.16.0.64 is OK now, and 172.16.0.42 is NOT OK now. > > The two commands you have requested give the following output for these > IP addresses: > > These are OK: > > # ip route get 172.16.0.64 > 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 > cache > # ip route get 172.16.0.59 > 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 > cache > > These are NOT OK: > > # ip route get 172.16.0.37 > 172.16.0.37 dev eth0 src 172.16.1.22 > cache <redirected> ipid 0x97a4 > # ip route get 172.16.0.42 > 172.16.0.42 dev eth0 src 172.16.1.22 > cache <redirected> ipid 0x0d21 > > These are OK: > > # ip route list cache match 172.16.0.59 > 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 > cache > # ip route list cache match 172.16.0.64 > 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 > cache > > These are NOT OK: > > # ip route list cache match 172.16.0.37 > 172.16.0.37 dev eth0 src 172.16.1.22 > cache <redirected> ipid 0x97a4 > 172.16.0.37 from 172.16.1.22 dev eth0 > cache <redirected> ipid 0x97a4 > 172.16.0.37 from 172.16.1.22 dev eth0 > cache <redirected> ipid 0x97a4 > # ip route list cache match 172.16.0.42 > 172.16.0.42 dev eth0 src 172.16.1.22 > cache <redirected> ipid 0x0d21 > 172.16.0.42 from 172.16.1.22 dev eth0 > cache <redirected> ipid 0x0d21 > > > How can I fix this? > > Thanks! We are working on it (see threads in netdev) You can in the meantime echo 0 >/proc/sys/net/ipv4/conf/eth0/accept_redirects ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: routing bug? 2011-11-18 13:33 ` Eric Dumazet @ 2011-11-18 13:38 ` Pozsár Balázs 2011-11-18 13:54 ` Eric Dumazet 0 siblings, 1 reply; 7+ messages in thread From: Pozsár Balázs @ 2011-11-18 13:38 UTC (permalink / raw) To: Eric Dumazet Cc: Sven-Haegar Koch, Linux-Kernel-Mailinglist, Tamási János, netdev On 2011-11-18 14:33, Eric Dumazet wrote: > Le vendredi 18 novembre 2011 à 14:23 +0100, Pozsár Balázs a écrit : > >> On 2011-11-18 14:09, Eric Dumazet wrote: >> >>> Le vendredi 18 novembre 2011 à 13:48 +0100, Sven-Haegar Koch a écrit : >>> >>> >>>> Added netdev list to CC:, there you should have a higher chance of a >>>> usefull answer. >>>> >>>> On Fri, 18 Nov 2011, Pozsár Balázs wrote: >>>> >>>> >>>> >>>>> Hi all, >>>>> >>>>> I have been struggling with this not easily reproducible issue since a while. >>>>> I am using linux kernel v3.1.0, and sometimes routing to a few IP addresses >>>>> does not work. What seems to happen is that instead of sending the packet to >>>>> the gateway, the kernel treats the destination address as local, and tries to >>>>> gets its MAC address via ARP. >>>>> >>>>> For example, now my current IP address is 172.16.1.104/24, the gateway is >>>>> 172.16.1.254: >>>>> >>>>> |# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:1B:63:97:FC:DC >>>>> inet addr:172.16.1.104 Bcast:172.16.1.255 Mask:255.255.255.0 >>>>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 >>>>> RX packets:230772 errors:0 dropped:0 overruns:0 frame:0 >>>>> TX packets:171013 errors:0 dropped:0 overruns:0 carrier:0 >>>>> collisions:0 txqueuelen:1000 >>>>> RX bytes:191879370 (182.9 Mb) TX bytes:47173253 (44.9 Mb) >>>>> Interrupt:17 >>>>> >>>>> # route -n >>>>> Kernel IP routing table >>>>> Destination Gateway Genmask Flags Metric Ref Use Iface >>>>> 0.0.0.0 172.16.1.254 0.0.0.0 UG 0 0 0 eth0 >>>>> 172.16.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 >>>>> | >>>>> >>>>> I can ping a few addresses, but not 172.16.0.59: >>>>> >>>>> |# ping -c1 172.16.1.254 >>>>> PING 172.16.1.254 (172.16.1.254) 56(84) bytes of data. >>>>> 64 bytes from 172.16.1.254: icmp_seq=1 ttl=64 time=0.383 ms >>>>> >>>>> --- 172.16.1.254 ping statistics --- >>>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>>>> rtt min/avg/max/mdev = 0.383/0.383/0.383/0.000 ms >>>>> root@pozsybook:~# ping -c1 172.16.0.1 >>>>> PING 172.16.0.1 (172.16.0.1) 56(84) bytes of data. >>>>> 64 bytes from 172.16.0.1: icmp_seq=1 ttl=63 time=5.54 ms >>>>> >>>>> --- 172.16.0.1 ping statistics --- >>>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>>>> rtt min/avg/max/mdev = 5.545/5.545/5.545/0.000 ms >>>>> root@pozsybook:~# ping -c1 172.16.0.2 >>>>> PING 172.16.0.2 (172.16.0.2) 56(84) bytes of data. >>>>> 64 bytes from 172.16.0.2: icmp_seq=1 ttl=62 time=7.92 ms >>>>> >>>>> --- 172.16.0.2 ping statistics --- >>>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms >>>>> rtt min/avg/max/mdev = 7.925/7.925/7.925/0.000 ms >>>>> root@pozsybook:~# ping -c1 172.16.0.59 >>>>> PING 172.16.0.59 (172.16.0.59) 56(84) bytes of data. >>>>> From 172.16.1.104 icmp_seq=1 Destination Host Unreachable >>>>> >>>>> --- 172.16.0.59 ping statistics --- >>>>> 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms >>>>> | >>>>> >>>>> When trying to ping 172.16.0.59, I can see in tcpdump that an ARP req was >>>>> sent: >>>>> >>>>> |# tcpdump -n -i eth0|grep ARP >>>>> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode >>>>> listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes >>>>> 15:25:16.671217 ARP, Request who-has 172.16.0.59 tell 172.16.1.104, length 28 >>>>> | >>>>> >>>>> and /proc/net/arp has an incomplete entry for 172.16.0.59: >>>>> >>>>> |# grep 172.16.0.59 /proc/net/arp >>>>> >>>>> 172.16.0.59 0x1 0x0 00:00:00:00:00:00 * eth0 >>>>> | >>>>> >>>>> Please note, that 172.16.0.59 /is/ accessible from this LAN from other >>>>> computers. >>>>> >>>>> >>>>> Does anyone have any idea of what's going on? Thanks, >>>>> >>>>> >>>>> Balazs Pozsar >>>>> >>>>> ps: I think it is related to this one: https://lkml.org/lkml/2011/11/16/292 >>>>> >>>>> -- >>>>> >>>>> >>> Could you send us result of : >>> >>> ip route get 172.16.0.59 >>> ip route list cache match 172.16.0.59 >>> >>> >> I did not tell you in my first mail, that some times different hosts are >> reachable and unreachable. I will try to not confuse you :) >> As of now, 172.16.0.59 is OK, and 172.16.0.37 is NOT OK. >> Also, 172.16.0.64 is OK now, and 172.16.0.42 is NOT OK now. >> >> The two commands you have requested give the following output for these >> IP addresses: >> >> These are OK: >> >> # ip route get 172.16.0.64 >> 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 >> cache >> # ip route get 172.16.0.59 >> 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 >> cache >> >> These are NOT OK: >> >> # ip route get 172.16.0.37 >> 172.16.0.37 dev eth0 src 172.16.1.22 >> cache<redirected> ipid 0x97a4 >> # ip route get 172.16.0.42 >> 172.16.0.42 dev eth0 src 172.16.1.22 >> cache<redirected> ipid 0x0d21 >> >> These are OK: >> >> # ip route list cache match 172.16.0.59 >> 172.16.0.59 via 172.16.1.254 dev eth0 src 172.16.1.22 >> cache >> # ip route list cache match 172.16.0.64 >> 172.16.0.64 via 172.16.1.254 dev eth0 src 172.16.1.22 >> cache >> >> These are NOT OK: >> >> # ip route list cache match 172.16.0.37 >> 172.16.0.37 dev eth0 src 172.16.1.22 >> cache<redirected> ipid 0x97a4 >> 172.16.0.37 from 172.16.1.22 dev eth0 >> cache<redirected> ipid 0x97a4 >> 172.16.0.37 from 172.16.1.22 dev eth0 >> cache<redirected> ipid 0x97a4 >> # ip route list cache match 172.16.0.42 >> 172.16.0.42 dev eth0 src 172.16.1.22 >> cache<redirected> ipid 0x0d21 >> 172.16.0.42 from 172.16.1.22 dev eth0 >> cache<redirected> ipid 0x0d21 >> >> >> How can I fix this? >> >> Thanks! >> > We are working on it (see threads in netdev) > > You can in the meantime > > echo 0>/proc/sys/net/ipv4/conf/eth0/accept_redirects > Unfortunately it does not solve the problem for me, I have have these "cache <redirected>" entries even after that echo command. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: routing bug? 2011-11-18 13:38 ` Pozsár Balázs @ 2011-11-18 13:54 ` Eric Dumazet 0 siblings, 0 replies; 7+ messages in thread From: Eric Dumazet @ 2011-11-18 13:54 UTC (permalink / raw) To: Pozsár Balázs Cc: Sven-Haegar Koch, Linux-Kernel-Mailinglist, Tamási János, netdev Le vendredi 18 novembre 2011 à 14:38 +0100, Pozsár Balázs a écrit : > Unfortunately it does not solve the problem for me, I have have these > "cache <redirected>" entries even after that echo command. > Its a problem with a cached value. You must reboot to flush it. It was already discussed yesterday on netdev. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2011-11-18 13:54 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-11-18 12:00 routing bug? Pozsár Balázs 2011-11-18 12:48 ` Sven-Haegar Koch 2011-11-18 13:09 ` Eric Dumazet 2011-11-18 13:23 ` Pozsár Balázs 2011-11-18 13:33 ` Eric Dumazet 2011-11-18 13:38 ` Pozsár Balázs 2011-11-18 13:54 ` Eric Dumazet
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